New Formulation Could Offer Improvements in
Cost-Effectiveness and Convenience for the U.S. Government's
Stockpile of Biodefense Countermeasures

ANNAPOLIS, Md., July 15 /PRNewswire-FirstCall/ -- PharmAthene,
Inc. (NYSE Amex: PIP), a biodefense company developing medical
countermeasures against biological and chemical threats, today
announced results from a New Zealand White Rabbit study showing
that its lyophilized recombinant Protective Antigen (rPA) anthrax
vaccine was more immunogenic than a liquid formulation of rPA
vaccine and produced a robust response with only 2 doses.

The data were presented in a poster presentation entitled
"Enhanced Immunogenicity in the New Zealand White Rabbit Model from
a Lyophilized Anthrax Vaccine that is Reconstituted at
Point-of-Use" at the 2010 International Conference on Emerging
Infectious Diseases by Dr. Elizabeth Leffel, Director of
Non-Clinical Sciences at PharmAthene.

Dr. Valerie Riddle, Senior Vice President and Medical Director
for PharmAthene, commented, "Recently, the bipartisan Commission on
the Prevention of Weapons of Mass Destruction Proliferation and
Terrorism reiterated concerns that the United States is failing to
address the threat posed to our citizens and military from a
possible biological attack. As we learned following the supply
shortages last year of H1N1 vaccine, it is critically important
that our government ensure we have adequate quantities of safe and
effective medical countermeasures to deter or respond to a
bioterror attack. PharmAthene is committed to innovating and
developing next generation anthrax vaccines and anti-toxins that
offer improvements over earlier technologies, and we look forward
to continued successful collaboration with our partners at the
National Institutes of Health (NIH) and at the Office of the
Biomedical Advanced Research and Development Authority (BARDA) of
the U.S. Department of Health and Human Services, to advance these
important medical countermeasures to protect Americans at home and
on the battlefield."

Lyophilized rPA Findings Reported

The study, which was funded by the National Institute of Allergy
and Infectious Diseases, part of the National Institutes of Health,
was designed to assess if PharmAthene's lyophilized rPA vaccine
reconstituted at point-of-use produced a more robust immune
response than liquid rPA vaccine and whether the immune response
from the lyophilized rPA changed over time following
reconstitution.

In the study, one group of New Zealand White rabbits (NZW)
received liquid rPA (1.0 microgram dose) stored at 2-8 degrees
Celsius via intramuscular injection on days 1 and 29. The remaining
four groups of NZW rabbits received lyophilized rPA (1.0 microgram
dose) stored at 2-8 degrees Celsius, reconstituted and administered
via intramuscular injection on days 1 and 29. Blood samples were
collected pre-dose and on days 15, 29 and 43 for measurement by
toxin neutralization assay (TNA) and enzyme linked immunosorbent
assay (ELISA) for the presence of IgG anti-PA antibodies.

Results demonstrated that lyophilized rPA vaccine, reconstituted
at less than 2 hours prior to use, was more immunogenic than the
liquid rPA vaccine when measured by both TNA and ELISA (p<0.05).
The study investigators concluded that lyophilized rPA
reconstituted at point-of-use was more immunogenic than liquid rPA
and produced a robust immune response after only 2 doses.

"We're very encouraged by this preliminary study," continued Dr.
Riddle. "The initial non-clinical animal data suggest that a
lyophilized rPA vaccine formulation may be able to provide
protection against anthrax infection with fewer doses than a liquid
vaccine formulation. We will be conducting additional studies to
confirm these preliminary results. In addition, a lyophilized
formulation could yield important practical advantages in the
field."

Previously, the Company announced that its lyophilized rPA
vaccine candidate was structurally stable and potent at various
temperatures up to and including 70 degrees Celsius. One of the
goals of PharmAthene's rPA program is to develop a stable
cold-chain-free vaccine, which could be stored and distributed at
room temperature -- an important advantage for deployment in the
civilian Strategic National Stockpile.

The Institute of Medicine has declared an urgent need to develop
and stockpile next generation anthrax vaccines employing modern
vaccine technology, which offer the potential for improved safety,
convenience, cost-effectiveness, and more rapid immunity.
PharmAthene is committed to working with its partners in the United
States government to address this need.

Funding for the lyophilized rPA vaccine program was provided
under a Challenge grant (UC1 AI067223) from the National Institute
of Allergy and Infectious Diseases, part of the National Institutes
of Health.

About Anthrax

According to the Centers for Disease Control and Prevention,
anthrax is an acute infectious disease caused by the spore-forming
bacterium Bacillus anthracis. Anthrax most commonly occurs in
hoofed mammals and can also infect humans. Symptoms of disease vary
depending on how the disease is contracted, but usually occur
within seven days after exposure. The serious forms of human
anthrax are inhalation anthrax, cutaneous anthrax, and
gastrointestinal anthrax. Initial symptoms of inhalation anthrax
infection may resemble a common cold. After several days, the
symptoms may progress to severe breathing problems and shock.
Inhalation anthrax is often fatal, even if treated by antibiotics.
Currently, antibiotics are the only drugs available for therapeutic
or prophylactic use for inhalation anthrax, and post-exposure
prophylaxis is the only FDA-approved indication for such products.
However, antibiotic therapy, while useful, is believed to be
associated with a number of limitations, including: (1) lack of
activity against the toxins produced by the B. anthracis bacteria,
(2) need for long-term dosing to achieve full protection,
complicated by side effects and non-compliance, (3) lack of
efficacy when administered late in the anthrax disease cycle, and
(4) lack of effectiveness against multi-drug resistant or
genetically engineered strains of anthrax.

About PharmAthene, Inc.

PharmAthene was formed to meet the critical needs of the United
States and its allies by developing and commercializing medical
countermeasures against biological and chemical weapons.
PharmAthene's lead product development programs include:

Except for the historical information presented herein, matters
discussed may constitute forward-looking statements within the
meaning of the Private Securities Litigation Reform Act of 1995
that are subject to certain risks and uncertainties that could
cause actual results to differ materially from any future results,
performance or achievements expressed or implied by such
statements. Statements that are not historical facts, including
statements preceded by, followed by, or that include the words
"potential"; "believe"; "anticipate"; "intend"; "plan"; "expect";
"estimate"; "could"; "may"; "should"; or similar statements are
forward-looking statements. PharmAthene disclaims, however, any
intent or obligation to update these forward-looking statements.
Risks and uncertainties include risks associated with the
reliability of the results of the studies relating to human safety
and possible adverse effects resulting from the administration of
the Company's product candidates, unexpected funding delays and/or
reductions or elimination of U.S. government funding for one or
more of the Company's development programs, the award of government
contracts to our competitors, unforeseen safety issues, challenges
related to the development, scale-up, and/or process validation of
manufacturing processes for our product candidates, unexpected
determinations that these product candidates prove not to be
effective and/or capable of being marketed as products as well as
risks detailed from time to time in PharmAthene's Form 10-K and
10-Q under the caption "Risk Factors" and in its other reports
filed with the U.S. Securities and Exchange Commission (the "SEC").
In particular, significant additional non-clinical animal studies,
human clinical trials, and manufacturing development work remain to
be completed for our lyophilized rPA anthrax vaccine candidate. At
this point there can be no assurance that this product candidate
will be shown to be safe and effective and approved by regulatory
authorities for use in humans. Copies of PharmAthene's public
disclosure filings are available from its investor relations
department and our website under the investor relations tab at
www.PharmAthene.com.